1. Field of the Invention
The present invention relates to a portable wireless LAN terminal device that is attachable to an external connecting terminal installed in a portable external connection device, such as a portable data terminal device, a portable data terminal system having a portable wireless LAN terminal device and an external connection device, and a mobile phone that is attachable to a portable wireless LAN terminal device.
In addition, the present invention relates to a wireless communication method that uses a portable wireless LAN terminal device, a method for providing service using a portable data terminal system, and a method for transferring an incoming call using a portable wireless LAN terminal device.
2. Background Information
A wireless LAN communication system can be easily constructed by buying a market available personal computer, radio base station, or the like. The aforementioned can provide users with a communication system at a relatively low price. In addition, the data transmission speed of a wireless LAN communication system is high, and is suitable for transmission and reception of a large amount of data. Examples of such a conventional wireless LAN communication system are shown in Japanese Laid-open Patent Publications 2003-110751, 2003-23674, HEI 10-51274, HEI 10-271120, 2002-261773, and 2000-224645, for example, which are hereby incorporated by reference. The especially relevant portions can be respectively found on page 3-4, FIG. 1, page 3-8, FIG. 1, page 2-4, FIG. 1, page 3-5, FIGS. 1-2, page 2-3, FIG. 1, and page 3-9, FIG. 1.
JP2003-110751 discloses a system for communicating using a wireless LAN circuit and a mobile phone circuit of a mobile phone with a wireless LAN terminal function installed therein, or with a PC card, which has a wireless LAN terminal function, attached thereto.
JP2003-23674 discloses a system for IP phone communications through a wireless LAN circuit by a slave unit connected to a PHS master unit as a mobile terminal unit, which has a wireless LAN terminal function installed therein through a PHS circuit or the PHS master unit itself.
JP-HEI 10-151274 discloses a system for a fighting game that can be played in competition with others by communicating between portable game terminal devices, which include a wireless LAN terminal function installed therein through a wireless LAN circuit.
JP-HEI 10-271120 discloses a system with a desktop or notebook personal computer (PC) connected to a wireless LAN terminal device by a cable for communication by selecting an available channel from a plurality of channels, which is divided from the specified frequency band of wireless LAN communication electric waves when the PC and a wireless communicate to a base station through the wireless LAN circuit.
JP2002-261773 discloses a system in which a wireless base station detects whether a wireless LAN terminal device, which is connected to a personal computer (PC) via a cable, has been stolen. The wireless LAN terminal device has a function that measures signal intensity from the wireless base station. When the intensity is lower than a predetermined value, the wireless LAN terminal device transmits a particular packet containing a MAC address to the wireless base station.
JP2000-224645 discloses a system for managing the historical travel of a wireless LAN terminal device by a management device connected to a wireless base station. The wireless LAN terminal device detects self-historical travel, and transmits it to the wireless base station.
In the first three patent references, the devices that perform the function of the wireless LAN terminal are installed in the mobile phone or the mobile terminal device (PHS master unit). However, in such a construction, the power consumption of the mobile phone or mobile terminal device is large. Accordingly, the available time allowed by a battery is relatively short. On the other hand, in order to increase the available time allowed by the battery, a battery with large capacity is required. Thus, the mobile phone and other components may be larger than desired. In addition, a shield for preventing interference between the electric wave of mobile phone circuit, and so on, and the electric wave of wireless LAN circuit is required. This may cause the construction of the mobile phone or the mobile terminal device to be larger than desired.
Additionally, when the PC card type wireless LAN terminal device is connected to the mobile phone or the mobile terminal device and is used, electric power is supplied to the PC card from the mobile phone or the like. Accordingly, power consumption of the mobile phone or the mobile terminal device is large. Similarly, this may exacerbate the above problem. Further, a slot exclusively used for attaching the PC card is required. This may cause the construction of the mobile phone or the mobile terminal device to be even larger.
Since the wireless LAN terminal device disclosed in the fourth or fifth reference does not have a user interface in the wireless LAN terminal device itself, the wireless LAN terminal device is required to be used while connected to a personal computer, or the like. Thus, the wireless LAN terminal device cannot be used in a stand-alone mode. Moreover, JP2000-224645 does not concretely disclose the construction of the mobile unit and how the function of the wireless LAN terminal is achieved.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved wireless LAN terminal Device, portable data terminal system, mobile phone, wireless LAN communication method, method for providing service, and method for transferring incoming calls. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.